1. Field
The present disclosure belongs to graphene technology and relates to high density and high hardness graphene-based porous carbon materials, methods for making the same, and applications using the same.
2. Background
Graphene is a single atomic layer of graphite, namely a two-dimensional sheet of sp2-bonded carbon atoms which are densely packed in a honeycomb or hexagonal crystal lattice. Graphene has excellent electrical, mechanical, thermal, and optical properties. Since its discovery in 2004, widespread attention and research continues.
Graphene in fact is always close to us. Even in pencil scratch on paper, we can find its presence. However, normally prepared graphene is a powdery material with a low density and a messy accumulation, which causes difficulties for direct utilization. To satisfy the needs for application, a graphene-based material with a certain macroscopic structure has to be made. Just like graphite, graphene is difficult to directly form the macroscopic shape. Certain methods, such as sol-gel method (Marcus A. Worsley et al. Synthesis of Graphene Aerogel with High Electrical Conductivity, J. Am. Chem. Soc., 2010, 132 (40), 14067-14069), hydrothermal method (Yuxi Xu et al., Self-Assembled Graphene Hydrogel via a One-Step Hydrothermal Process, ACS Nano, 2010, 4, 4324-4330), and chemical self-assembly method (Wei Lv et al., One-Pot Self-Assembly of Three-Dimensional Graphene Macroassemblies with Porous Core and Layered Shell, J. Mater. Chem., 2011, 21, 12352-12357), can be adopted to indirectly form a graphene assembly. Yang et al. prepared a graphene-based porous three-dimensional assembly by using a hydrothermal method with an introduction of bonding agent (Chinese patent application number CN 201010568996.8). However, like other aerogel materials, this three-dimensional porous assembly also has a low density and an absence of hardness.
In general, in related art, the first thing for the graphene-based materials is forming a macroform with a special microstructure through interlinkage of graphene sheets together. The shapability and hardness of the assembly do not draw much attention.
What is needed, therefore, is a highly compact graphene assembly with a high-density and high-hardness but retain a high porosity, a method for making the same, and worthwhile applications using the same.